Concrete structures used to be considered semi-permanent. However, in recent times, it has become popular to demolish and then rebuild concrete structures for reasons of deterioration, out-of-date conditions, economic disadvantages, and the like. In this connection, various methods and apparatus for demolishing concrete structures have been proposed.
For example, such proposed methods for demolishing concrete structures include: an impact demolition method using hammers and chisels, impact breakers, steel balls, or the like; a mechanical demolition method using lock jacks, crushers, cutters, drills, or the like; a thermite demolition method using metallic-wire thermite, thermite moldings (refer to Japanese Patent Application Laid-Open No. 48-67414), or the like; a flame demolition method using jet flame or the like; an explosive demolition method; a gas expansion demolition method; an electrical demolition method using arc discharge, laser, plasma arc (refer to Japanese Patent Application Laid-open No. 55-145294), or the like; and a jet demolition method using water jet, sand jet, or the like.
Each of the conventional demolition methods has both merits and demerits. A comparative study can be made on the merits and demerits of the various demolition methods, the structure and size of the object to be demolished, environmental concerns, and other factors, to collectively evaluate the demolition methods for a particular structure. Then, a demolition method best suited for that structure can be employed. However, in the case of demolishing concrete at a high efficiency, the proposed methods involve the occurrence of a secondary problem due to the noise, flying dust and chips, and the like.